Polymerization of acrylonitrile-alpha methyl styrene mixtures onto polybutadiene and products produced thereby



Oct 3, 1959 w. c. CALVERT 08,661

POLYMERIZATION OF ACRYLONITRILE-ALPHA METHYL STYRENE MIXTURES ONTOPOLYBUTADIENE AND PRODUCTS PRODUCED THEREBY Filed Jan. 11, 1957 20Po/yu/ad/ene can/e07 of Polymers United States Patent A 2,908,661Patented Oct. 13, 1959 products of this invention constitute distinctlynew and BUTADIENE AND PRODUCTS PRODUCED THEREBY William C. Calvert,Gary, Ind., assignor to Borg-Warner Corporation, Chicago, 111., acorporation of [11111018 Application January 11, 1957, Serial No.633,750

5 Claims. (Cl. 26045.5)

The present invention relates to graft copolyrners of polybutadiene,alpha methyl styrene and acrylonitrile and the method for making thecopolymers. As used in this specification, and as defined in the Reporton Nomenolature of the International Union of Pure and AppliedChemistry, Journal of High Polymer Science, volume 8, page 260, the termgraft copolymer designates a high polymer, the molecules of whichconsist of two or more polymer parts of different compositions,chemically united together. A graft eopo lym'er may be produced, forexample, by polymerization of a given kind of monomer With subsequentpolymerization of another kind of monomer onto the product of the firstpolymerization.

My copending application, Serial Number 383,379, filed September 30,1953, describes and claims the preparation of polymeric products by theinteraction, under polymerizing conditions, of a conjugated diolefinepolymer latex with a mixture of a vinyl aromatic and a vinyl cyanide.While the greater part of this copending application is devoted todescriptions of the preparation of polymeric products by theinteraction, under polymerizing conditions, of a polybutadiene latexwith a mixture of styrene and acrylonitrile, Example 4 thereof disclosesthe preparation of polymeric products bythe interaction, underpolymerizing conditions, of a polybutadiene latex with a mixture ofalpha methyl styrene and acrylonitrile. It was therein stated thatreplacement of styrene by alpha methyl styrene resulted in theproduction of polymeric products having softening points considerablyhigher than those of polymeric products made using styrene.

Additional work with the polybutadiene latex: alpha methylstyrenezacrylonitrile system and more extensive testing of the polymericproducts resulting from the interaction, under polymerizing conditions,of the components of this system, confirmed the higher softening pointsof the polymeric products formed and, in addition, demonstrated thatthese polymeric products were superior in many other respects topolymeric products formed by the interaction, under polymerizingconditions, of a po lybutadiene latex with a mixture of styrene andacrylonitrile. Thus, polymeric products resulting from the interaction,under polymerizing conditions, of a polybutadiene latex with a mixtureof alpha methyl styrene and acrylonitrile, I

in addition to exhibiting higher softening points than polymers in whichstyrene Was employed in the manufacturing process in place of alphamethyl styrene, also exhibited higher impact values, far superior agingproperties, and enormously enhanced resistance, when in stressedcondition, to various chemical agents in comparison with the behavior ofpolymers produced by the interaction, un-

der polymerizing conditions, of a polybutadiene latex with a mixture ofstyrene and acrylonitrile. The differences in physical and chemicalproperties between the two types of polymeric products are quite new andunexpected and many of these differences are very distinctly differencesin kind rather than differences in degree. As will become apparent fromthe subsequent exposition, the polymeric ess for the preparation ofsolid novel compositions of matter.

One object of this invention is to provide a process for the preparationof new and improved solid polymeric products.

A further object of this invention is to provide a proc polymericproducts eX- hibiting a high impact value.

Yet another object of this invention is to provide a process for thepreparation of solid polymeric products exhibiting a high heatdistortion temperature.

An additional object of this invention is to provide a process for thepreparation of solid polymeric products exhibiting a high resistance toaging.

A further object of this invention is to provide a process for thepreparation of solid polymeric products exhibiting a high resistance,when exposed in stressed condition, to various chemical agents.

Also, it is an object of this invention to provide solid polymericproducts exhibiting improved physical and chemical properties.

Another object of this invention is to polymeric products of high impactvalue.

An additional object of this invention is to provide solid polymericproducts exhibiting .a high heat distortion temperature. Y

A further object of this invention is to provide solid polymericproducts exhibiting a high resistance to aging;

Yet another object of this invention is to provide solid polymericproducts exhibiting a high resistance, when exposed in stressedcondition, to various chemical agents.

Other objects of this invention will become apparent as the descriptionthereof proceeds.

This invention will be fully understood from a consid eration of thefollowing 'co'mplete'descrip'tions of a number of specific embodimentsthereof in connection with the accompanying single sheet of drawingforming a part of this specification, said single sheet of drawing beinga graphical representation of the impact values of the polymericproducts 'of this invention as a function of the polybutadiene contentthereof, compared with similar data for polymeric products of the'priorart in which styrene was employed in the manufacturing process in placeof the alpha methyl styrene. It is to be understood that the specificembodiments presented below are illustrative only and the spirit andscop'e of the invention is not necessarily limited thereto.

A EXAMPLE 1 The following polymerization mixtures were prepared, thefigures in Table I being parts by weight.

provide solid Table 1 Formula L M N O 55 Polybutadiene latex 36. 36 54.54 72. 72 90. 9 Polybutadiene equivalent 20 30 4 50 Alpha methylstyrene". 51 45 38 '32 Acrylonitrile 29 25 22 18 Oumene hydropero 0. 750. 65 0.55 0. 45 Dresinate No. 731 .8 2. 4 -2.-() 5 0. 5 0.5 6 0. 146 0.146 5 0. 0. 125 O 1. 0 1. 0 5 0. 05 0. 05 .4 167. 0 159. 0

NorE.-Dresinate No. 731 is the sodium salt of hydrogenateddisproportionated rosin. Darvan No. '1 is'the sodium salt of polymerizedalkylaryl sulfonic acid.

Polymerization was effected in six hours at 50 C., us.- ing a rotanngglass reactor. 'I he laticeslproduced were stablhzed by the addition of1.2% by weight, based on the SOlldS content of the resulting latices,ofdi-t-butyl p- -cresol-and then coagulated in dilute sulfuric acid."The Table II Formula L M N O Tensile strength, lbs/sq. in 5,933 4, 4173, 904 3, 476 Elongation, percent 28 112 147 170 Set, percent 18 93 115115 Bursting strength 465NB 465NB 375NB 270NB Softening point, C 112. 5110. 5 106.0 99. 5 Brittle point, (3.. l2. 65. 0 70. 0 73. Shore Dhardness- 80 75 70 61 Impact resistance Excellent Excellent ExcellentExcellent NorE.Bursting strength determined on Mullen paper tester usingsheets 0.040 inch thick. NB designates Samples that did not rupture.Impact strength determined by sharply striking a sheet A inch thickagainst a corner of a stone slab.

EXAMPLE 2.

The polymerization recipes of this example were the same as those ofExample 1 with the very important exception that in the present examplestyrene was used in place of the alpha methyl styrene of Example 1. Thepolymerization procedure, method of product recovery, purification andprocessing were the same in both examples.

The following Table III shows the weight ratiospolybutadiene:styrenezacrylorritrile employed in the variouspolymerization recipes of the present example together with test data onthe polymeric products obtained.

Table III Formula H F I J Polybutadiene, dry basis 20 30 40 50 S ene 6145 38 32 29 25 22 v 18 Tensile strength, lbs/sq. in 5, 982 4, 938 3, 8923, 585 Elongation, percent 22 12 135 173 Set, percent 17 105 118Bursting strength 588 515NB 370NB 27ONB Softening point, C 94. 5 97. 590. 0 86. 0 Brittle point, G 25. 0 -62. 6 -70. 0 -73. 5 Shore D hardness80 76. 6 70 65 Impact resistance. Good Excellent Excellent Excellent Acomparison of physical test data on the styrene containing polymers ofthis example with corresponding data on the alpha methyl styrenecontaining polymers of Example 1 will show that the only reallysignificant difference between the two types of polymers resides intheir softening points (heat distortion temperatures). The softeningpoints of the alpha methyl styrene containing polymers of Example 1 arefrom 13 to 18 C. higher, averaging C. higher, than the softening pointsof corresponding styrene containing polymers of the present example.

There is some indication that the impact resistance of certain alphamethyl styrene containing polymers may be higher than that ofcorresponding styrene containing polymers but the test method hereemployed to determine this property was so qualitative that thedifferences shown are hardly significant. With respect to the otherphysical properties determined, alpha methyl styrene containing polymersand corresponding styrene containing polymers appear to be identical.

EXAMPLE 3 In order to measure more accurately the differences inphysical properties between alpha methyl styrene containing polymers andstyrene containing polymers, a large number of polymer samplescontaining alpha methyl styrene were prepared and tested as set forth inthis example.

Limiting consideration for the moment to the polybutadiene, alpha methylstyrene and acrylonitrile components of the polymerization recipes,three series of runs were made, the polybutadiene in the four individualruns of each series comprising 10%, 20%, 30% and 50% by weight of thethree component mixture, the alpha methyl styrene plus acrylonitrileaccordingly comprising 90%, 70%, and 50% by weight, respectively, of thethree component mixture. In one series of runs the alpha methylstyrene/acrylonitrile weight ratio was held constant at 2.1, in a secondseries this ratio was 1.8 while in the final series this ratio was 1.5.

In addition to the three major components of the polymerization recipesconsidered in the previous paragraph, each polymerization recipecontained, per 100 parts by weight polybutadiene plus alpha methylstyrene plus acrylonitrile, the following additional materials in partsby weight:

NOTE.DaXad No. 11. Polymerlzed sodium salts of alkyl naphthalenesulfonic acids. Cerelose is a. commercial dextrose.

In all instances the recipes were polymerized under agitation in a glassflask at 60 C. and the polymer formed was recovered from the resultingreaction product, purified and then further processed as set forth inExample 1 hereof.

The following Table IV gives the parts by weight of polybutadiene, alphamethyl styrene and acrylonitrile used in each individual run. Asmentioned previously,

each individual polymerization recipe also contained the additionalingredients set forth in the listing immediately above. Table IV alsopresents physical test data on the individual polymers produced.

Table IV Fflrm"1a 1 2 a 4 5 e 7 s 9 10 11 12 55% Polybutadiene latex 1,1 gage 4, 4 90,0 18,18 36.36 54.54 90.9 18.18 36.30 54.54 90.9 y ta eneeq a ent" 1o 20 30 50 10 20 3o 50 10 20 so 50 Alp a met yl styrene 6154. 2 47. 4 33. 35 57.8 51. 45 45 32. 15 54 48 42 30 acrylonitrile 2925. s 22. o 16. 15 32. 2 2s. 55 25 17. a5 36 32 23 20 Alpha methylstyrene/acrylonitrile weight Mi 2.1 2.1 2.1 2.1 1.8 1.8 1.8 1.8 1.5 1 51.5 1.5 Heat distortion temperature, C. (ASTM D648-45T) 9s. 0 105. o102. o 102 101 100 103. 5 97. 5 99 98 9 5 93. 5 Rockwell hardness, Rscale (ASTM 13785-51). 111 104 28 112 102 84 113 101 84 Notched Izodimpact strength at 228 0.,

foot pounds per inch of. notch (ASTM D-758-48) 1.6 .4 8,6 10.5 1.8 3.79.3 10.3 2.6 5.4 7.6 9.3 Fadeometer exposure in hours before samplefalls in 20 F. falling ball test p 0 22 OK 0 22 88 OK 44 22 44 44 aftera t The physical properties of the polybutadiene-alpha methylstyrene-acrylonitrile polymers prepared as above described were,compared, with those of polybutadienestyrene-acrylonitrile. polymers.In. all. instances comparisons were made between polymers haying thesame polybutadiene content and'the same vinylaromatic/acrylonitrileweight ratio., 'v

The data of Table IV show that at constant alpha methylstyrene/acrylonitrile, ratios, the heat distortion,

temperature is. not generally affect'edby the polybutadiene content ofthe polymer, especially at intermediate values of polybutadiene,content. ,There is. evidence however that at ratios of 1.8 and 1.5 theheat distortion temperature of polymers, containing 50% polybutadiene islower than that of polymers containing lesser amounts of polybutadiene.At the 2.1 ratio the opposite appears to be true, the heat distortiontemperature of the polymer containing 10% polybutadienebeing lower thanthat of poly mers containing larger amountsv of polybutadiene. There isno question that the. alpha methyl styrene/.acrylonitrile ratio has. aslight but definite effect on heat distortion temperature, the heatdistortion. temperature as a rule decreasing slightly as this ratio.decreases.

The heat distortion temperatures of polybutadienestyrene-acrylonitrilepolymers exhibit the same variations with changes in composition, as dopolybutadiene-alpha methyl styreneeacrylonitrile poly'mersbut the heatdistortion temperatures of polybutadiene-styrene-acrylonitrile polymersare. always very appreciably lower than those of polybutadiene-alphamethyl styrene-acrylonitrile polymers of corresponding composition. Thusa, typical 30:45:25 polybutadiene-styreneacrylonitrile polymer (compare,Formula 7, Table IV); has a heat distortion temperature of only 84 C.

Table IV demonstrates that the alpha methyl styrene/ acrylonitrileratio. has no measurable effect on the Rockwell hardness (R scale) of;the polymers but that polybutadiene content has a marked influence onhardness. As the polybutadiene content is: increased from. 10% to 50%,the hardness falls from about 112 toa value; below 30. Polybutadienestyrene-acrylonitrile polymers exhibit a similar trend.Polybutadiene-alpha methyl styreneacrylonitrile polymers generally havea very slightly lower Rockwell hardness (R scale) thanpolybutadiene-styreneacrylonitrile polymers of correspondingcomposition. At a vinyl aromatic/acrylonitrile ratio of 2:1,polybutadienestyrene-acrylo'nitrile polymers have a hardness to 2 unitshigher than that of polybutadiene-alpha methyl styrene-acrylonitrilepolymers of corresponding composition; when this ratio is 1.8 thehardness difference is from 0 to 4 unitsand at a ratio of 1.5 thehardness diiference is from 2, to- 7 units. In general, the differencein hardness between the two types of polymers is least whenpolybutadienecontent is low, the difference increasing with increasing polybutadiene.content.

The notched Izod impact strength of polybutadienealpha methylstyrene-acrylonitrile polymers is not influenced in any regular fashionby the alpha;methyl styrene/acrylonitrile ratio used. in preparing thepolymers but the polybutadiene. contentof the Polymer has a very markedefiect on the impact strength exhibited. As the polybutadiene content ofthese polymers increases from 10% to 50%, the notched Izod impactstrength in foot pounds per inch of notch increases from about 2 toabout 10. r

The notched Izodimpact strengths of polybutadienestyrene-acrylonitrilepolymers is always appreciably lower than those of polybutadiene-alphamethyl styrene-acrylonitrile polymers of corresponding composition. Thefollowing Table V shows the average impact strengths (taken from TableIV) of polybutadiene-alpha methyl styrene-a'crylonitrile polymers of thedesignated constant polybutadiene content together with correspondingdata on polybutadiene-styrene-acrylonitrile polymers of the samepolybutadiene content. Since, as mentioned previously, vinylaromatic/acrylonitrile ratio has no ob= servable eflect on impactstrength, the averages include polymers in which this ratio ranges from2.1-1.5 to 1.

Table V Notched Izod Impact Strength, Foot Pounds Y PolybutadieneContent, Percent Polybutadiene I Polybutadiene- Alpha Methyl Styrene-Styrene- Acrylonitrile Acrylonitrile Polymers Polymers The single sheetof drawing that accompanies this specification and is a part thereof isa graphical representation of the data presented in Table V whereinsmooth curves are drawn through the two sets of average experimentaldatum points presented in this table. At a low polybutadiene content-(10%) the impact values of the two types of polymer are both low but theimpact value of the polybutadiene-alpha methyl styrene-acrylonitrilepolymer is almost three times as great as the impact value of thepolybutadiene-styreneacrylonitrile polymer. As polybutadiene contentincreases, the impact values of the resulting polymeric productsincrease also but the impact value of a polybutadiene-alpha methylstyrene-acrylonitrile polymer is invariably appreciably greater thanthat of a polybutadiene-styrene-acrylonitrile polymer of correspondingcomposition but the percentage difference between the two impact valuesbecomes less as the polybutadiene content increases. Thus, at 50%polybutadiene content, the impact value of the polybutadiene-alphamethyl styrene-acrylonitrile polymer is 43% greater than that of thepolybutadiene-styrene-acrylonitrile polymer.

An accelerated test was developed to evaluate the resistance to aging ofthe polymeric products of this invention. Experiments demonstrated thatthe results of this accelerated test correlated very well with theresults obtained in actual out-of-doors exposures which, of course,usually had to be continued for inordinately long periods of time toresult in failure.

In this accelerated test, the polymeric product was sheeted to athickness of 0.080 inch and the resulting sheet was cut into a six bysix inch test panel. The test panel was exposed for a predeterminedperiod of time to radiation in a Fadeometer. After exposure, the testpanel was held at 20 F. for four hours in a cold box. At the end of thisperiod, the panel was rapidly centered in a horizontal position on asteel supportingring having a central hole 3% inches in diameter, thepanel being held in firm contact with the steel supporting ring by a.clamping device. This panel mounting device also. held in the cold boxand was centered below an opening (which was usually closed with a plug)in the lid of the cold box. After mounting the panel, the resultingassembly was allowed to rest undisturbed in the cold box for anappreciable time-at least five minutesimmediately following which theplug was removed from the opening in the lid of the cold box and a 535g. steel ball (approximately 19 ounces) was dropped from a height of 4.5feet through the opening in the lid of the cold box onto the center ofthe area of the horizontally mounted test panel that Was supported bythe steel ring. Following this drop test the' panel was examined forevidence of cracking which was considered to represent failure due toaging.

Of course, in determining the resistance to aging of an individualpolymeric product, a number of test panels prepared from the polymerwere exposed to radiation in the Fadeometer, each test panel beingexposed for an individually predetermined period of time. Then the ex;

posed panels were separately subjected to the previously described 20'F. falling ball test to determine the number of hours Fadeometerexposure required before failure occurred in the 20" F. falling balltest.

Table IV shows that at alpha methyl styrene/acrylonitrile weight ratiosof 2.1 and 1.8, the aging resistance of the polymers generally increaseswith increasing polybutadiene content. At these ratios and atpolybutadiene content, the polymers fail in the F. falling ball testeven if not exposed in the Fadeometer but at 50% polybutadiene contentthe polymeric products withstand the -20 F. falling ball test even after371 hours exposure in the Fadeometer. At an alpha methylstyrene/acryl'onitrile ratio of 1.5, polybutadiene content has no sucheffect on aging resistance. At this iow ratio, the 10% polybutadienecontent polymershows a high resistance to aging (in contrast to failurewithout exposure of 10% polybutadiene polymers at the higher ratios). Atthe 1.5 ratio, the 50% polybutadiene content polymer shows a highresistance to aging but not the interminably long resistance to agingexhibited by the 50% polybutadiene content polymers of 1.8 and 2.1ratios.

The aging resistance of polybutadiene-alpha methyl styrene-acrylonitrilepolymers is very much higher than that ofpolybutadiene-styrene-acrylonitrile polymers of correspondingcomposition. Thus, polybutadiene-styreneacrylonitrile polymerscorresponding to Formulas 6, 7 and 8 of Table IV (with, of course,styrene used in place of alpha methyl styrene) required Fadeometerexposures of, respectively, 0, 22, and 22 hours before failing in the 20F. falling ball tests. Corresponding exposure times ofpolybutadiene-alpha methyl styrene-acrylonitrile polymers, taken fromTable IV, are, respectively, 22, 88 and (no failure after) 371 hours.

The polybutadiene-styrene-acrylonitrile polymers described briefiyherein and in more detail in my aforementioned copending application areuseful in the fabrication of plastic pipe. However, it has been foundthat such polymers, when under stress, are not resistant to a number ofchemical agents and this fact seriously limits the range ofapplicability of pipe made from such polymers and also limits the use ofthe material. as a chemically resistant liner for drums, vessels and thelike. However, it has been found that polybutadiene-alpha methylstyrene-acrylonitrile polymers, even when under stress, resist theaction of chemical agents that will destroy stressedpolybutadiene-styrene-acrylonitrile polymers in from less than a minuteto a few hours.

In testing the chemical resistance of polymers when under stress, astrip was cut from a standard ASTM slab of the polymer and was bent andinserted into a spring clamp, the spring clamp holding the test strip ina bent, stressed position. The resulting assembly was then immersed inthe selected chemical, denatured alcohol and a 10% aqueous solution ofpotassium permanganate being here employed, these two materials havingbeen found to be among the most active chemicals in causing failure ofstressed polymers.

A stressed test strip of a polyhutadiene-alpha methvlstyrene-acrylonitrile polymer did not develop any cracks when immersedin denatured alcohol for one week. A similarly stressedpolybutadiene-styrene-acrylonitrile test strip failed in denaturedalcohol in less than one minute.

A stressed test strip of a polybutadiene-alpha methylstyrene-acrylonitrile polymer did not develop any cracks when immersedin 10% aqueous potassium permanganate solution for one week. A similarlystressed polybutadiene-styrene-acrylonitrile 'test strip failed in 10%aqueous potassium permanganate solution in less than 12 hours.

These stressed chemical resistance tests described in the previousparagraphs embraced a sufiicient number of controls and replicates toassure that the results were not due to non-uniformity in either teststrips or spring clamp tensions. 1

8 EXAMPLE 4 Somewhat modified polymerization recipes and polymerizationprocedures were employed in the runs of this example. Confiningattention for the moment to polybutadiene, alpha meth'yl styrene andacrylom'trile, in all instances the polybutadiene comprised 30%by.weight of the three component mixture, alpha methyl styrene 45% byweight and acrylonitrile 25% by weight thereof. (Alpha methylstyrene/acrylonitrile weight ratio, 1.8.)

In addition to the three major components of the polymerization recipesmentioned above, with one exception to be specifically mentionedsubsequently, each polymerization recipe contained, per parts by weightof the polybutadiene-alpha methyl styrene-acrylonitrile mixture, thefollowing materials in parts by weight:

Para menthane hydroperoxide 0.73 Dresinate No. 731 1.96 Sodiumpyrophosphate decahydrate 1.5 Sodium hydroxide 0.15 Daxad No. 11 0.13Fructose 0.5 Ferrous sulfate heptahydrate 0.034 Mixed tertiarymercaptans 0.5 Water 182.7

N0TE.Mixed tertiary mercaptans designate a mixture of C12, C14 and C10tertiary alkyl mercaptans in approximately 60 20 20 weight ratio. Mixedtertiary mercaptans were employed in Formulas 13, 14 and 15 of Table VIto follow but mixed tertiary merca-ptans were not present in Formula 16of said table.

Table VI Formula 13 14 I 15 I 16 Heat distortion temperature, C. (ASTMD785- 82 86 87 74 Notched Izod impact strength at 22.8 0.,

foot pounds/inch of notch (ASTM D758-48). 6. 7 8. 1 7. 3 7. 3

N0 mixed tertiary mereaptans used in the recipe.

The first three runs of Table VI are duplicate experiments. Comparingthe physical properties of the polymeric products produced in thesethree runs with those of corresponding polymers shown in Table IV(Formulas 3, 7 and 11) it is seen that the heat distortion temperatureand Rockwell hardness (R scale) of the two groups of polymers areessentially identical. The impact strength of Formulas 13, 14 and 15polymers is a little lower (averaging about one foot pound lower) thancorresponding polymers of Table IV.

The resistance to chemical agents when under stress was determined usingthe polymeric product resulting from the polymerization of Formula 13These tests were run as described in Example 3. The Formula 13 polymer,stressed as previously described, was not affected when immersed forfour days in denatured alcohol or in 10% aqueous potassium permanganatesolution. A polybutadiene-styrene-acrylonitrile polymer of correspondingcomposition when tested similarly failed in less than one minute indenatured alcohol and failed after seven hours immersion in 10% aqueouspotassium permanganate solution.

9 EXAMPLE Table VII presents information on a number of polymerizationrecipes (in parts by weight) and certain physical properties of thepolymeric products obtained by the polymerization of theserecipes. Thepolymerization recipes are rather similar to that of Formula 7 of Table'IV (data on this formula being repeated in Table VII to facilitatecomparisons) although the individual polymerization recipes differedfrom that of Formula 7 in at least one significant respect asspecifically set forth below.

[in all formulations, polybutadiene comprised 30%. by weight of thepolybutadiene-alpha methyl styrene-acrylonitrile mixture. Alplia methylstyrene and acrylonitrile comprised, respectively, 45% by weight and 25%by weight of this three component mixture, the alpha methylstyrene/acrylonitrile weight ratio being 1.8. Individual fixedquantities of cumene hydroperoxide, sodium pyrophosphate, ferroussulfate, Daxad' No. 11 and Cerelose were used in all recipes.

Formula 17 is similar to Formula 7 except that Formula 17 contains nopotassium oleate and a polymerization temperature of 65 C. (instead of60 C.) was employed. Formula 18 diifers from Formula 17 in thatDresinate No. 731 was increased from 1.96 to 5.0 parts by Weight.

Formula 7 has previously been discussed. Formulas 19, 20 and 21 areduplicate runs and are similar in all respects to Formula 7. However, inFormulas 19, 20 and 21 the polymerization temperature was 65 C. insteadof the 60 C. employed in the polymerization of Formula 7. A

In Formulas 22, 23 and 24, the potassium oleate used in Formulas 19-21was replaced by increasing amounts of Rubber Reserve flakes (soap).

Formula 25 is similar to Formula 18 with the exception that Formula 25contains 0.5 part by weight mixed tertiary mercaptans.

Formulas 26 and 27 are similar to Formulas 19-21 with the exception thatthe recipe of Formula 26 con tains 0.5 part by weight tertiary octylmercaptan while that of Formula 27 contains 0.5 part by weightdiisopropyl dixanthogen.

sary to perform a series of replicate standard experiments and treat thedata obtained by statistical methods and then determine if data obtainedin another series of replicated experiments, run under conditions otherthan those selected as standard, differ bya statistically significantamount from the results of the standard experiments. The data of TableVII, considered in conjunction with the data obtained in a number ofadditional replicate experiments show that the variations. inpolymerization recipes and polymerization conditions set forth in TableVII and outlined in the previous discussion have no significant effecton the physical properties set forth in Table VII of the polymersproduced.

Since any variations in the physical properties listed in Table VlII arenot statistically significant, it is proper to average the individualvalues of eachproperty listed. On this basis, the average heatdistortion temperature of these polymers is 101 C., the average Rockwellhardness (R scale) is 85 and the average notched Izod impact strength is7.9 foot pounds per inch of notch.

These average values diiier in a statistically significant manner fromthe average value of theI-same physical properties ofpolybutadiene-styreneacrylonitrile polymers of correspondingcomposition. Thus, the heat distortion temperature ofpolybutadiene-alpha methyl styrene-acrylonitrile polymers is very muchhigher (10 C., or more, higher), the impact strength is appreciablyhigher (about 3.0 foot pounds per inch of notch higher), while theRockwell hardness (R scale) is very slightly but significantly lower(about 3 units lower) than corresponding values exhibited bypolybutadiene-styreneacrylonit'rile polymers of correspondingcomposition.

As used herein, the terms (a) polybutadiene-alpha methylstyrene-acrylonitrile polymers and (b)polybutadiene-styrene-acrylonitrile polymers designate the polymericproducts formed by the interaction, under polymerizing conditions, of(a) a polybutadiene latex, alpha methyl styrene and acrylonitrile and(b) a polybutadiene latex, styrene and acrylonitrile.

As used herein, the term corresponding composition as applied to aplurality of polymers designates polymers resulting from theinteraction, under polymerizing conditions, of mixtures containingidentical weight per- Table VII Formula 17 18 7 19 20 21 22 23 24 25 2627 Polybutadiene latex. 54. 54 54. 54 54. 54 54. 54 54. 54 54. 54 54. 5454. 54 54. 54 54. 54 54. 54 54. 54 Polybutadiene equivalent 30 30 30 3030 30 30 30 30 30 Alpha methyl styrene 45 45 45 45 45 45 45 45 45 45 4545 ,Acrylonitrilt 25 25 25 25 25 25 25 25 25 25 25 25 Cumenehydroperoxide 0. 73 0. 73 0. 73 0. 73 0.73 0. 73 0. 73 O. 73 0. 73 0. 730, 73 73 Dresinate No. 731 1. 96 1.96 1. 96 1.96 1. 96 1. 96 5. 0 1, 961, 9 Sodium pyrophosphate, anhyd1ous 0. 5 0. 5 0. 5 00. 5 0. 5 0. 5 0. 50. 5 0. 5 Sodium hydroxide 0. 15 0. l5 0. l5 0. 15 0. l5 0. 15 0. 15 0.l5 0. 15 Daxad No. 11- 0.13 0.13 0.13 13 0.13 0.13 0. 13 0.13 0.13Cerelose 1.0 1.0 1.0 1.0 1.0 1. 0 1.0 1.0 1.0 Ferrous sulfateheptahydrate. 0. 011 0.011 0.011 0.011 0.011 0.011 0. 011 0. 011 0. 011Water a. 184. 5 184. 5 182. 0 182. 0 183. 2 184. 5 187. 0 182. 0 182, 0Potassium oleate 2. 0 2.0 2.0 2. 0 2 0 Rubber Reserve flakes 1. Mixedtertiary alkyl mercaptans- Tertiary octyl mercaptan. Diisopropyldixanthogen Polymerization temperature, 0 Heat distortion temperature,C. (AS'IM D648-45T) 100.0 103. 0 108. 5 100.0 101.0 103. 5 102. 5 98.599. 0 100. 5 102. 5 100.0 Rockwell hardness, R scale (ASTM 13785-51). 8792 86 80 85 87 89 88 82 Notched Izod impact strength at 228 C. Ft.

lbs/inch notch (ASTM D758-48) 7. 7 -5 3 8.1 6. 7 9. 7 8. 3 7.2 6.5 8.28.1 6. 9

As will be obvious to those skilled in the art, in work of the typeherein described, involving a complicated group of polymerizationreactions occurring in a very complex reaction mixture, absolutecorrespondence between the results of duplicate experiments is not to beexpected. Not only are the polymerization reactions in- 7 volved verycomplex but, in addition, some components of the reaction mixture areused in very minute amounts and these minor components have an extremelypronounced effect on the speed and the course of the polymerizationreactions. In such circumstances it is neces- 5 centages of lapolybutadiene latex, a vinyl aromatic and acrylonitrile.

This application is in part a continuation of my copending application,Serial Number 383,379, filed September 30, 1953.

Be it remembered, that while this invention has been described inconnection with specific details and specific embodiments thereof, thesedetails and embodiments are illustrative only and are not to beconsidered limitations 'on the spirit or scope of said invention exceptin so far as they may be incorporated in the appended claims.

I claim: 7

1. A process for the production of synthetic resins comprisingpolymerizing, at a temperature in the approximate range 50 C. to 80 C.,amixture of acrylonitrile and alpha methyl styrene in the presence ofpolybutadiene present in the form of an aqueous polybutadiene latex.

2. A process for the production of synthetic resins comprisingpolymerizing, at a temperature in the approximate range 50 C. to 80 C.,from about 40 to about 90 parts by weight of a mixture of alpha methylstyrene and acrylonitrile in a weight ratio within the approximate range1.52.1 to 1.0 in the presence of from about 60 to about 10 parts byweight polybutadiene present in the form of an aqueous polybutadienelatex.

3. A process for the production of synthetic resins comprisingpolymerizing, at a temperature in the approximate range 50 C. to 80 C.,from about 60 to about 80 parts by weight of a mixture of alpha methylstyrene and acrylonitrile in a weight ratio within the approximate range1.5-2.1 to l, in the presence of about 40 to about 20 parts by weightpolybutadiene present in the form of an aqueous polybutadiene latex.

References Cited in the file of this patent UNITED STATES PATENTS2,356,091 Roedel Aug. 15, 1944 2,688,009 Crouch Aug. 31, 1954 2,755,270Hayes July 17, 1956 2,802,808 Hayes Aug. 13, 1957 FOREIGN PATENTS679,562 Great Britain Sept. 17, 1952 UNITED STATES PATENT oTFTcECERTIFICATE OF CORRECTION Patent No 2,908,661 October 13, 1959 WilliamCO Calvert It is herebj certified that error appears in the -printedspecification of the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 3, Table II first line, for "5,933" eighth column thereof 0013 -asecond column thereof, under the heading "L", read m 5,993 columns 9 and10, Table VII, under the heading "22", ninth line, for 13" read Signedand sealed this 12th day of April 1960o (SEAL) Attest:

KARL Ha AXLINE ROBERT C. WATSON Attesting Officer Commissioner ofPatents

1. A PROCESS FOR THE PRODUCTION OF SYNTHETIC RESINS COMPRISINGPOLYMERIZING AT A TEMPEATURE IN THE APPROXIMATE RANGE 50*C. TO 80*C., AMIXTURE OF ACRYLONITRILE AND ALPHA METHYL STYRENE IN THE PRESENCE OFPOLYBUTADIENE PRESENT IN THE FORM OF AN AQUEOUS POLYBUTADIENE LATEX.